Sounds like an accusation. It is.
Take for example web standards. Don't try to feed us your crap that you have and are actively participating in all sorts of initiatives. That's great but it's the people you employ who are doing that. It is the enthusiasm of human creativity.
But because the majority of people still use a shitty browser (I grant you that it has gotten better, but let's not depart from the point), web developers are forever stuck programming with the lowest level denominator only because IE6 has to be supported. Or because IE7 or IE8 incorrectly implemented something.
How can a browser slow down the internet? Because it slows down progress by not allowing programmers to evolve and educate at higher levels. Language evolution is but an academic exercise, not something that can be popularized by mass adoption. Forget about great ideas, they won't work for your clients.
Can anything be done? At all?
I wait for inertia to catch up. IE will fall. The weight of the giant will leave it behind.